Dice the chicken breast into small, even bite-sized pieces.
In a small bowl, whisk together the sriracha, tamari, rice vinegar, garlic powder, onion powder, and red pepper flakes to create the spicy glaze.
Place a non-stick skillet over medium-high heat and add 2 tablespoons of water.
Add the chicken to the skillet and cook until opaque and cooked through, about 5-7 minutes, adding more water if the pan becomes too dry.
While the chicken cooks, steam the broccoli florets in a separate pot or microwave until tender-crisp and bright green.
Pour the spicy glaze over the chicken in the skillet and toss to coat thoroughly until the sauce thickens slightly.
Place the warm cooked white rice in a bowl and top with the glazed chicken and steamed broccoli.
Serve immediately, drizzling any remaining sauce from the pan over the top.